Kotlin Code Coverage: Measuring Quality with JaCoCo and Gradle

Writing tests for your Kotlin applications is only half the battle; knowing which parts of your codebase are actually executed is crucial for maintaining high software quality. This text-only course guides you through setting up, generating, and interpreting code coverage reports specifically tailored for Kotlin's unique language features. You will transition from guessing your test effectiveness to confidently identifying untested execution paths using JaCoCo. What you'll learn: - Understand the fundamentals of code coverage metrics, including line, branch, and instruction coverage. - Configure JaCoCo within Kotlin projects using both Gradle (Kotlin DSL) and Maven build systems. - Generate and interpret detailed HTML and XML coverage reports to find gaps in your test suite. - Exclude compiler-generated code, such as Kotlin data classes and inline functions, to ensure accurate metrics. - Set up coverage verification rules to automatically fail builds when coverage thresholds are not met. - Apply modern testing practices by integrating JaCoCo with JUnit 5 and mock frameworks. You will start with core testing and coverage terminology before moving step-by-step through build configuration, report generation, and advanced exclusion rules. The written explanations and practical code examples ensure you can immediately apply these configurations to your own projects. This course is designed for beginner Kotlin developers and QA engineers looking to improve their testing workflows; no prior experience with JaCoCo is required. Start reading today to bring transparency and confidence to your Kotlin test suites.